Fluid motor



May 28 1940 H. F. PARKER 2,202,023

FLUID MOTOR Filed 001'.. 17, 1956 6 Sheets-Sheet 1 j 4 EL 72j f /c A T T ORNE YS.

H. F. PARKER FLUID MOTOR May 28, 1940.

6 Sheets-Sheet 2 Filed Oct. 17, 1936 117 VEA/TOR Hawking; F )gdr-1??? [32 @a A m m N M T T A May 28, 1940. F, PARKER 2,202,023

` FLUID MOTOR Filed oct. 1'1,l 193e @sheets-sheet s INVENTOR Hmyrey 7:" Par/ien A TT ORNE YS.

May 28, 1940. H, F, PARKER 2,202,023

" FLUID Moron Filed oct. 17, 195e 6 sheets-sheet 4 INVENTOR May 28, H F. PARKER 2,202,023

FLUID MOTOR Filed Oct. 17, 1936 6 Sheets-Sheet 5 (gaa 5 4m 45s "592 390 INI/ENTOR 45 40? 404 584.352 Humprfg 'ref:

A TTORNE Ys.

May 23 1940 H. F. PARKER I 2,202,023

FLUID MOTOR Filed Oct. 17, 1936 6 Sheets-Sheet 6 Si @www BY Hymyrey 77 Zoff/'herz 4a4 ,552 v q 4 @ai M2124# @wok/VMM.

Patented May 28, 1940 -UNITED STATES PATENT OFFIQE FLUID MOTOR Humphrey F. Parker, Detroit, Mich.

Application October 17, 1936, Serial No.v 106,134

8 Claims. (Cl. 121-150) The present invention relates to fluid pressure which the movements of the reversing valve are operated motor mechanisms, and in particular selectively controlled by passages associated With provides improvements in fluid pressure operated and partially formed by the motor piston rod; motors adapted particularly for use in connection and to provide a motor construction as above with vehiclev windshield wiper systems. generally Stated f' the single acting piston type Objects of the present invention are to provide in which the movements of the piston in one improvements in fluid pressure operated motors, direction are controlled by fluid pressure and in and to provide motor constructions which may which the movements of the piston in the other be economically manufactured and assembled and direction are effected by Spring DIGSSUIB- l0 which afford positive and eflicient operation; to With the above and other, as Well as more 10 provide improvements Which may be embodied specic objects in view, preferred but illustrative in fluid pressure operated motors of either the embodiments of the invention are shown in the vane or the piston type; to provide improvements accompanying draWiDgS, thrOughOut Which Corre- .which may be embodied in motors adapted to be Sponding reference characters are used to desigautomatically brought to rest at selected predehat@ COITSDOldIlg Darts, and Il WhiChI 15 termined positions in the normal stroke thereof Figure 1 is a general view in elevation showing or in positions beyond the normal stroke thereof; the general arrangement of a vehicle Windshield and to provide improvements which may be em- Ollelatlg System embdylg an improyed motor.

bodied in motors adapted for variable speed op- 0f the present HVGDOD;

zu eration. Fig. 2 is a view in end elevation of the vane 2o Further objects of the present invention are to type mOOl ShOWIl generally in Fig. l; provide improved fiuid'p-ressure operated motor Fig. 3 is a View in rear elevation of the immechanisms utilizing reversing valve mechanisms proved Vane 'GyDS IDOOIJ 0f the uid pressure operated type; to provide Fig. i isa View in Vertical longitudinal Section,

5 such constructions in which the reversing valve taken along the line lof Fig'. 2; mechanisms is movable in one direction under Fig. 5 is a View in vertical longitudinal section,

the iniiuence of nuid pressure, and is movable in taken along the line 5 5 of Fig. 2; the other direction under the influence of spring Fig. 5a is a fragmentary view of a modification pressure; to provide such constructions in which of the structure of Figs. 2 through 9, and correg-U the movement of the vane or piston controls the spOnding generally to Fig. 5; 3o supply to, and discharge of, actuating fluid from Fig. 6 is a View in vertical transverse section, the valve mechanism; to provide such constructaken along the line 6-6 of Fig. 3; tions in which the stopping of the motor in a Fig. 7 is a View in vertical transverse section, selected position may be effected by controlling taken along the line -'l of Fig. 3;

33 the supply of iiuid to the valve; to provide such Fig. 8 is a view in vertical longitudinal section, 35

constructions in which the stop control mecha taken along the line 8-8 of Fig. 6; nism may be arranged to bring the motor to rest Fig. 9 is a View corresponding generally t0 Fig. v

at a normal limit position or at a position beyond 3, but showing the motor vane in a different opsuch normal limit position; to provide such coneration position;

im structions embodying improved means including Fig. 10 iS a View in Vertical aXial Section of a 0 secondary passages to insure completion of the llOdiCalOD 0f the 11101501 ShOWIl fl Figs. 1 valve movements in each instance; and to provide through 9; motor constructions of the above generally stated Fig. 11 is a view in vertical section, taken along type in which the selectively operable shut-off the line il--ll of Fig. l0;

l5 valve may be provided with means to vary the Fig l2 is a view in vertical section, taken along 45 speed of operation of the motor, as well as to efthe line l2-l2 of Fig. l0; fect the starting and stopping thereof. Fig. 13 is a View in vertical section of a further Further objects of the present invention are modification of the motor shown in Figs. 1 to provide a motor of the above generally dethrough 9;

scribed character of the oscillating vane type, in Fig. 14 is a view in vertical section, taken along 50 which the movements of the valve are selectively the line lll-I4 of Fig. 13; controlled by passages formed in and controlled Fig. l5 is a vievv in end elevation of a motor by the shaft oi' the vane; to provide a motor conof the double acting piston type; struction of the above generally described ar- Fig. 16 is a view in vertical longitudinal section,

rangement. of the double acting piston type, in. taken along the line lli-I6 of' Fig. 15; 55

Cil

Fig. 17 is a view in horizontal section, taken along the line Ii-I'l of Fig. 15;

Fig. 18 is a view in vertical transverse section, taken along the line lB-l of Fig. 16;

Fig. 19 is a view in horizontal section, taken along the line lQ-iS of Fig.

Fig. 20 is a view in vertical transverse section, taken along the line 2li- 20 of Fig. 16;

Fig. 21 is a view corresponding generally to Fig. 16 but showing the piston in the opposite limit position;

Fig. 22 is a view in vertical transverse section corresponding generally to Fig. 2O but illustrating the adaptation of the motor for control by a parking valve;

Fig. 23 is a View in top plan oi the invention as embodied in a motor of the single acting piston type;

Fig. 24 is a view in end elevation of the motor shown in Fig. 23;

Fig. 25 is a view in vertical longitudinal section, taken along the line P25-25 of Fig. 24;

Fig. 26 is a view in vertical longitudinal section, taken along the line 26-26 of Fig. 24;

Fig. 2'7 is a view in vertical longitudinal section, taken along the line 'zi- 2l of Fig. 24;

Fig. 28 is a view in horizontal section, taken along the line 28--18 of Fig. 24;

Fig. 29 is a view in horizontal section, taken along the line 29-29 of Fig. 24;

Fig. 30 is a view in vertical transverse section, taken along the line 38-36 of Fig. 23;

Fig. 31 is a view in vertical transverse section, taken along the line 3 I-Sl of Fig. 23;

Fig. 32 is a view in vertical transverse section, taken along the line 32--32 of Fig. 23;

Fig. 33 is a view in vertical transverse section, taken along the line 33--33 of Fig. 23;

Fig. 34 is a view in vertical transverse section, taken along the line Sli- 34 of Fig. 23;

Fig. 35 is a view in vertical transverse section, taken along the line 35-35 of Fig. 23; and

Figs. 36 and 37 are diagrammatic views based upon the motor of Figs. 23 through 35, showing the piston thereof in opposite extreme positions, and showing, in schematic form, the arrangements of the valve passages.

A preferred application of the improved iiuid pressure motors of the present invention is in connection with the operation of the windshield Wiper mechanisms of automobiles. It will be appreciated, however, from a complete understanding of the invention, that the improved motors may be used in widely different applications. Preferably also, the motors are designed to be operated by positive fluid pressure, and the preferred actuating uid is lubricating oil which may, where the motors are associated with ve` hicles, be derived from the pressure lubrication system of the vehicle. Various other iiuids may, however, be used to provide the positive pressure for actuating the motors, and moreover in the broader aspects of the invention, suitable and hereinafter pointed out changes may be made in the present structures, adapting them to be operated by negative fluid pressures or suction, that is, by differential pressures represented by the difference between atmospheric pressure and a partial vacuum. Patent No. 1,731,048, granted to Holmes and the present applicant, discloses and generally claims the combination, in a vehicle windshield wiper system, of a fluid pressure motor disposed to be actuated by oil pressure derived from the vehicle lubrication system. In so far as the patented construction is concerned,

the present invention is directed principally to improvements in the structural features of the iiuid pressure motor.

Fig. 1 illustrates the general arrangement of the elements of an illustrative transmission system which may be used for transmitting mechanical movement from the present motor to a windshield Wiper system. In this figure, the windshield wiper 50, which may be of conventional construction, is disposed for rotation about an axis adjacent the base of the vehicle windshield. The transmission mechanism provided to elect the oscillation of the wiper 59, includes a pair of flexible operating cables 52 (Fig. 3) which extend downwardly from the underside of the vehicle cowl 54, within Sheaths 56, and terminate in opposed racks 58 and GO, which are in continuously meshing relation to an oscillating pinion 62. Pinion 62 is secured to the outer end of the shaft 64 of the motor, which is designated as a whole as 66. Motor 66, in turn, is adapted to be secured directly to the block of the engine 63. As described in more detail in the co-pending application, the racks 58 and 60 are retained 1n meshing relation to the pinion 62 by guide rollers 'l0 and 'l2 which are rotatably carried by the motor 66, and are connected to the cables 52 by lost motion connections, comprising the lugs 16 and 13. With this arrangement, oscillation of pinion 62, as hereinafter described, moves the racks 58 and 60 in respectively opposite directions. Each rack is thus eifective to pull its associated cable, but, because of its lost motion connection therewith, is ineiective to apply a pushing force therethrough. The return movement of each cable is effected through the mechanism connected thereto adjacent the base ol the windshield.

Referring now particularly to Figs. 2 through '7, the motor 66 comprises generally two castings 80 and 82, secured together in back-to-back relation by a plurality of studs 84, which pass through openings provided therefor adjacent the periphery of the outer casting 80, and are threaded into corresponding openings provided therefor in the inner casting 82. The inner casting 32, which is provided with a plurality of lugs 86, by which the motor as a whole may be secured to the block of the vehicle engine, or to any other suitable stationary supporting member, is formed to provide a generally semi-circular piston chamber 88, within which the vane 9D of the motor is oscillatably received. Casting 82 is also provided with a machined face 92 which is disposed to abut a correspondingly formed face provided on the engine 68. As hereinafter described, the face 92 is provided with a plurality of exhaust passages, which preferably extend directly through the wall of the engine block 68, into the crank case of the engine.

The outer casting 80 is provided with an under cut portion dened by the raised portions 9F. and 96, within which under cut portion the previously mentioned guide rollers IB and '12, the pinion 62, and the racks 58 and 5D are received. This under cut portion is adapted to be closed in the completely assembled condition of the parts by a cover plate 98. The rollers 'l0 and 'i2 are carried upon trunnions |06 and E62 individual thereto, which extend into recesses provided therefor in the casing 80. The cover plate 98 is secured in place by a plurality of studs 05 which are received in threaded openings |04 and |06 provided in bosses lll and IlD which project slightly outwardly from the base of the under-cut portion.

The castings Bil and 82 are bored to rotatably receive and to provide a bearing for the shaft 64 of the motor, which is slotted to receive the vane 9|), and which is provided with a reduced extension ||l to which the drive pinion 62 is secured. In order to prevent leakage around the shaft 64 and into the just mentionedundercut portion of casting 8E), a packing gland H5 is interposed between casting t!) and the shoulder |253 of shaft ili. The shoulder is retained in continuous engagement with packing gland H6 by a compression spring |22 which is received in a recess |24 formed in the inner end of shaft 60|. The outer end of spring |22 bears directly against the engine 58. In accordance with conventional practice, leakage around the vane Sii is minimized by packing members |26 and |28, which are secured to respectively opposite sides ofv the vane by rivets In addition to the above described elements, the motor 55 comprises a piston type shut-oil valve |32, which is slidable in a passage |35 provided therefor in the casting Sil, and a main reversing valve |36, also of the piston type, which is received in a passage |38 provided therefor in the upper portion ofthe casting'SZ. The shutoff valve |32 comprises an annular recess |40, deiined by the two portions |42 and IM. The right hand end of valve |32, as viewed in Figure 4, is connected to a flexible control cable M6. sheath |48 for the cable |45 is secured within a litting |59, which in turn is tightly secured in a recess cut into the casting 8|). Cable |436 extends, as shown in Figure 1, to the interior of the vehicle, and is provided with an operating button or handle |52. Valve |32 is shown in Figure i in the running position, in which the recess |1553 registers with the supply passages. To stop the motor, the cable |45 may be pushed to move valve |32 to the left, bringing the portion M4 into registry with the just mentioned passages and closing them 01T.

The reversing valve |35 is provided with two annularly recessedportions |69 and |52, separated by an enlarged portion Ifi. Enlarged portions lii and |58 are disposed adjacent the end of the valve. Valve |35 is provided with an axi- V `ally extending bore il', which receives a compression spring |72. Spring |i2, the free end of which bears against the enclosed end of the chamber |38, continuously urges valve |36 from the position shown to the opposite extreme position, in which the sto-p VM abuts the removable plug |75 which acts to enclose the end of the chamber |38. Movement of the valve |36 from the just mentioned limit position to the position shown in Figure is accomplished by admitting iiuid pressure into the chamber |38 between the end of the valve and the plug |75, as hereinafter described.

The various connecting passages, which supply fluid to the reversing valve tov determine the direction of operation of the vane 9i?, and by which the reversing movements of the valve |35 are controlled by the position of the vane and by the shutoff valve |32, may best be understood in connection with a description of operation of the motor. Throughout the following description, only the active passages are given reference characters. Any passages not given reference characters are dead-end passages, closed by removable plugs, which are formed, as will be un- The derstood, as an incident to the formation of the active passages. y

The reversing valve |36 is shown in Figure 5, in the position occupied thereby during the travel of thev vane in a counter-clockwise direction to the limit position shown in Figure 5. The arrival ofthe vane 9|! at the right hand limit position results in a reversing movement of the valve |36, but for purposes of clarity, the valve is illustrated as being in the position occupied thereby immediately prior to the reversal.

With valve |36 in the position shown in Figure 5, the iiuid circuits for causing counter-clockwise movement of the vane 90 are as follows. Fluid is admitted under pressure to the left hand, or lower side of vane Sil by way of the passage |85, which directly connects with the intake nipple H32 of the motor, around the recess |50, and through passage |84 directly into the vane chamber 88. .As will be appreciated, nipple |82 may be connected to a source of fluid pressure in a suitable way. The fluid circuit for exhausting luid from the upper or right hand side of the vane extends from the chamber 88, through the passage |86, around the recess |52, and through the exhaust passage |83 (Figure 6) into the Vehicle crank case. As long as these two uid circuits remain complete, as will be appreciated, vane 90 moves in the counter-clockwise direction, and ultimately reaches the position shown in Figure 5.

As vane |30 approaches the position shown in Figure 5, a fluid circuit is completed which exhausts the valve operating chamber |38 (between the end of the reversing valve |36 and the plug H6) permitting valve ist to be moved to its extreme left hand position under the influence of the compression spring |12. This exhaust fluid circuit extends (Figures 7, 5, fi and 6) from the chamber |38, through passage |96, connecting passage |92, passage |94, passage ist, radial shaft passage |93, axial shaft passage 25u, and thence into the sump 'by way of the spring recess lili. The radial shaft passage |93 registers with the connecting passage |96 only upon the arrival of the Vane 9B at the limit position shown in Figures 5 and 8 so that the just mentioned exhaust fluid circuit is completed only upon such arrival. Upon completion of the just traced iiuid exhaust circuit, the iiuid previously trapped in the chamber |38 is discharged therefrom, permitting the previously mentioned leftward movement of valve |36, Linder the influence of the compression spring |72, to the position shown in Fig. s.

The movement of valve |36 from the position shown in Figure 5 to the position shown in Figure 8, disconnects the passage i3d from the inlet passage ESQ and connects it to an exhaust passage 262 (Fig. 8) corresponding to the previously mentioned exhaust passage |88. Similarly, the valve movement disconnects the passage |85 from the exhaust and connects it to the inlet nipple |82. With the valve ist in the position shown in Figure 8 accordingly, fluid circuits are completed which exhaust the lower or left hand side of vane 9|? and which apply iiuid pressure to the right hand or upper side of vane at. The exhaust circuit extends from the chamber tt, through the passage |84, around the recess itil, and thence through the exhaust passage 2&2 to the sump. The fluid supply circuit extends from the intake passage |85, around the valve recess |32, and through the passage |86 into the chamber 88?. These uid circuits result in movement oi vane 90 in a clockwise direction, as viewed in Figures 5, 8 and 9. The initial movement of the vane 90 from the limit position shown in Figure to the position shown in Figure 8 interrupts the previously traced exhaust circuit for the valve chamber |38. This action is, however,'without effect, as this chamber is now evacuated and valve |36 is retained in its left hand limit position under the influence of spring |12.

As the vane 90 approaches the left hand limit position, a fluid circuit is completed, by which fluid is admitted under pressure to the valve chamber |38, causing valve |36 to move to the position shown in Figures 5 and 9, against the force of the compression spring |72. This fluid circuit extends (Figures 6, 4, 'l and 5) from the intake nipple |82, through a transverse passage 204, a vertical passage 206, around the recess |40 of the shutoff valve |32, through the vertical passage 208, through a valve recess 2 |0, cut in the motor shaft 64, and thence through the previously mentioned passages |96, |94, |92 and |98, into the valve chamber |38. The shaft recess 2|0 is so cut as to register with the passage |96 only when the vane 99 reaches the left hand limit position. Completion of the just traced fluid circuit supplies fluid under pressure to the chamber |38, causing a reverse movement of valve |36 as stated above.

The return movement of valve |36 to the position shown in Figures 5 and 9 recompletes the initially traced fluid supply and exhaust circuits for the chamber 88, causing a return movement of vane 90 in the counter-clockwise direction. The initial movement of the vane 90 from the left hand limit position to, for example, the position shown in Figure 9, moves the shaft valve recess 2|0 out of registry with the passage |96, interrupting the just traced fluid supply circuit for the valve chamber |38. Interruption of this fluid supply circuit, however, serves merely to trap the actuating fluid within the chamber |38, so that valve |38 remains in the right hand position until released, as above described, upon the arrival of the vane at the right hand limit of travel.

As long, accordingly, as the shut-off valve |32 remains in the running position (Fig. 4), the vane 90 of the motor 66 continuously reciprocates between the left hand and right hand limit positions thereof. At each arrival of the Vane 90 at the right hand limit position, the valve chamber |38 is exhausted, permitting the valve |36 to be moved to the left hand limit position under the influence of the spring |12. On the other hand, each arrival of the vane 90 at the left hand limit cf travel completes a fluid supply circuit for the valve chamber |38, resulting in a movement of the valve |36 to the right hand limit position against the influence of the compression spring |12.

Considering now the stopping of the motor, it will be appreciated that the shut-off valve |32 is associated only with the fluid supply circuit to the reversing valve chamber |38. A stopping movement of valve |32 thus serves only the purpose of preventing completion of a fluid pressure supply circuit for the valve |36. It may be assumed, for example, that shut-off valve |32 is moved from the position shown in Fig. 4 to the left to the stopping position during counterclockwise movement of the vane 90. This shutoff movement has no effect other than to discon` nect the passages 206 and 208 from each other, which, as previously described, are associated with the fluid pressure supply circuit for valve 36. Under the conditions mentioned, valve |36 occupies the position shown in Fig. 5, in which a quantity of fluid is trapped within the chamber |38. 'I'he uid pressure supply circuit for chamber |38 is interrupted at the shaft passage 2|0, so that the additional interruption thereof by the valve |32 is without immediate effect. When the vane 90 reaches the limit position shown in Fig. 5, the previously traced exhaust circuit is completed for chamber |38, which circuit is independent of the shut-off valve 32 and the completion of which, accordingly, is not eected by the stopping movement of the valve |32.

Upon the arrival of the vane 90 at the left hand limit of travel, the fluid pressure supply circuit for chamber |38, normally, completed through the shaft passage 2 0, is now interrupted at the valve |32. This fluid pressure supply circuit being interrupted, the arrival of the vane 90 at the left hand limit of travel is not accompanied by a reversing movement of the valve |36, and the fluid pressure thus acts continuously to urge the vane 90 in the clockwise direction, forcibly but yieldingly retaining it at rest in the left hand limit position. It is believed to be evident that if the shut-off movement of valve 32 takes place during clockwise movement of vane 90, the stopping action is the same; that is, vane 90 is brought to rest at its left hand limit of position as a result of the failure of completion of a fluid pressure supply circuit for the reversing valve |36. It is seen, therefore, that the shut-off valve |32 may be operated at any point in the operating cycle of the motor to pre-condition the motor to be stopped upon its next arrival at its left hand limit position.

The starting operation of the motor is effected simply by throwing shut-off valve |32 to the running position shown in Fig. 4, which action immediately re-completes the fluid pressure supply circuit for the valve chamber |38, it being noted that at this time, the transverse shaft passage 2|0 is in registry with the cooperating passage |96. Completion of this circuit effects the normal reversal of the valve |36 and initiates a counter-clockwise operation of the vane 90.

In certain instances, it is found desirable to so arrange the motor that in normal operation, the vane 90 oscillates through a pre-determined angular range but, when stopped, occupies a position beyond this normal range. This alternative arrangement is readily embodied in the motor of the present invention simply by so forming the transverse shaft passage 2|0, which serves, as above described, to control completion of the valve fluid pressure circuit, as to permit completion of this circuit slightly before the vane 90 reaches its absolute left hand limit of travel. With this relation, the normal reversal at the left hand position occurs slightly in advance of the otherwise permissible leftward limit of the vane 90. When, however, the shut-oil` valve |32 is moved to the closed position, preventing completion of the fluid pressure reversing circuit through the passage 2|0, the vane 90 is moved under the influence of the fluid pressure to its extreme maximum limit position. In practicing this alternative construction, it is, of course, desirable to so form the transverse shaft passage 2 0 that it is in registry with the passage fil) |93 not only at the normal reversing position of the vane but is also in registry therewith when the vane 99 occupies its maximum limit position. In all other respects, the construction and arrangement of the motor may be as specically shown in the figures described above.

Referring further to Figs. 5 and 9, the motor is provided with secondary passages 2|2 and 2M, which act to insure proper operation of the reversing valve |36 independently of any tendency of the actuating iluid to leak around the valve. The secondary passage 2 i2 is formed in the valve 35, and extends through the enlarged portion HEB thereof, forming a connection between the valve chamber |38 and the valve recess i60. 'Ihe passage 2M forms a connection between the chamber space between the right hand end of valve 35 and the sump. This passage extends through the inner wall 92 of the motor.

As is evident from Fig. 5, at any time that the reversing valve it occupies the right hand limit position shown, in which uid under pressure occupies the chamber |38, the valve recess |69 is connected to the supply passage H30. Any tendency of the iiuid trapped within the chamber i3?. therefore to escape therefrom due to leakage or other causes, is prevented, since the bleeder passage 2li connects the chamber |38 to the supply passage i, thus affording lchamber |38 a supply o1 iluid to compensate for any such leakage. i

As will be appreciated from Figs. 8 and 9, `the chamber space at the right hand end of valve i156 is continuously inl communication with the exhaust through the exhaust passage 2M. Any tendency, therefore, for fluid leaking around the enlarged portion |66 to build up a pressure on the right hand end of valve |35 is overcome.

Figure 5a illustrates the adaptation oi the construction o:i` Figures 2 through 9 for suctionoperation instead of for positive fluid pressure operation. In this instance, the reversing valve |3iia corresponds in all respects to the previously described valve E36 except that it is reversed in position. IZihe compression spring ilZa, received in the valve recess Elim, bears against the plug |16, and

thus continually urges the valve to the right instead of to the left as previously described. Also, the bleeder passage Eiil of Figure 5 is replaced by a passage 2|'Za' which connects the recessed portion it? with the valve bore lla, and consequently with the valve chamber space |38. In all other respects the construction and arrangement of parts may be as described in detail with reference to Figures 2 through 9 (as indicated by the use of corresponding reference characters), it being understood, of course, that the inlet i is connected to a source of suction, instead of iiuid pressure, and that all exhaust passages are connected to atmosphere.

As to operation, the parts are shown in Fig. 5a, in positions corresponding to rightward travel oi vane 99, vane 9i? being in its limit position and in readiness to eiiect a reversing movement of valve ita. It will be recalled from the description of Figures 2 through 9 that the arrival of vane 9@ at its right hand limit of travel connects the valve chamber |38 to the sump through the axial shaft passage it@ (Fig. 6). In this case this connection results in connecting chamber |38 to atmosphere. This connection either partially or entirely balances the atmospheric pressure acting on the right hand end of valve |380. (through pasf sage iii, Fig. 8) and renders spring IHla effective to force valve |36a to its right hand limit position.

In the just stated right hand limit position of valve Etta, the chamber space at the left hand side of vane 9@ is connected to suction, and chamber space at the right hand side of vane 90 is connected to atmosphere. The suction circuit includes the inlet passages 292i and |80, the valve recess |69 and passage itil. The atmospheric circuit includes passage ISS, the valve recess E62 and passage Hi8, which latter passage is more clearly shown in Figure S. During completion of these circuits, accordingly, vane 99 is acted upon by a pressure dirlerential which causes it to move in a clockwise direction, or to the left.

As vane approaches its left hand limit of travel, as previously described, the yvalve chamber ist is connected to the inlet |82, or, in this case, to suction, through the fluid circuit which includes the shaft valve recess 2l@ (Fig. 4). Upon completion of this circuit, chamber E33 is partially evacuated, rendering the atmospheric pressure acting on the right hand end of valve |36a effective to force the valve to the left against the force of spring illa.. This valve movement, as will be appreciated, reverses the suction and atmosp-heric connections to the vane chamber, re-

sulting in counter-clockwise or rightward movement of vane 90.

As long as the cut-off Valve 592 (not shown in Fig. 5a) remains in running position, valve 99 continuously reciprocates as in the case of the positive pressure operated motor of Figures 2 through 9. It is believed to be evident that if it is desired to stop the motor, the cut-off valve |32 may be operated to prevent the connection of chamber |33 to suction and to, accordingly, prevent a rightward reversing movement thereof upon the arrival of vane 99 at its right hand limit of travel. The motor thus parks as in the previous embodiment, except that in this case the parking position is at the right hand position instead of at the left hand limit position.

As described in connection with Figures 2 through 9, during the period that chamber |33 is intended to be partially evacuated, it is desirable to arrange the structure to prevent the building up of 'a pressure within this chamber; and during the time chamber ESE is intended to be under pressure, it is desirable to prevent a dissipation of this pressure. This is accomplished in Figure 5a` by bleeder passage 2 E Ila which extends through the wall of valve Etta and connects chamber' |33 to recess 62. Thus, movement of valve iSa to the position shown in Fig. 5a, which results from partially evacuating chamber |38, connects this chamber to suction through bleeder passage 2 |211. On the other hand, movement of valve Htc to its right hand position, which results from applying atmospheric pressure to chamber 33, connects this chamber to atmosphere through the bleeder passage 2|2a.

vReferring to Figs. l0, il and 12, an embodiment oi the invention is shown in which the stopping of the motor in a selected or parked position is effected by completing an auxiliary eX- haust circuit for 'the chamber associated with the reversing valve, instead of by interrupting the normal fluid pressure supply circuit therefor, as in the case or the motor of Figs. 2 through 9. Except insofar as concerns the shut-off mechanism, the structure of Figs. 10, 11 and 12 may be and preferably is the same as described in connection with Figs. 2 through 9. Accordingly, corresponding reference characters are used so far as applicable.

In Figs. l0, l1 and 12 the normal fluid supply circuit for the chamber |38 associated with the reversing valve |36 extends from the inlet nipple |82 through passages 204 and 296 to the shaft recess 2|0 and thence through passages |96, |92 and |90 into the valve chamber as previously described. It Will be recalled that recess 2|0 registers with passage 206 only when the motor vane reaches its lefthand limit of travel. The normal fluid exhaust circuit for the valve chamber |38 extends through the passages |90, |92 and |96 and thence through the radial shaft passage |98 into axial shaft passage 208 to exhaust. These circuits duplicate those described with reference to Figs. 2 through 9 except that the fluid supply circuit is not subject to the cut-olf valve |32.

In the embodiment now being described an auxiliary circuit extending from the chamber |38 to lexhaust is provided, which auxiliary circuit is subject to the shut-off valve |32a. This exhaust circuit extends from the chamber |38 through a transverse passage |99, a passage |97, vertical passage |95 to the valve |32a. From this point the circuit extends through a vertical passage |93 into an annular recess i9! provided on the shaft S4. Recess |9| communicates through a second radial shaft passage |89 which connects into the axial shaft passage 280 and thus returns to the sump. With the shut-off valve |32a in the running position shown in Fig. l1 the just traced auxiliary exhaust circuit is interrupted and, therefore, the reversing valve |36 is controlled by the main supply and exhaust circuits in the manner described with reference to Figs. 2 through 9.

In the event it is desired to bring the motor to rest, the valve |32a may be moved to the right from the position shown in Fig. 11 to a position in Which the annular recess |81 is into registry With the passages and |93. This action immediately completes a fluid exhaust circuit for the reversing valve chamber |38 permitting it to be moved to its lefthand limit position (Fig. 5) under the influence of the compression spring |72. In this position of the reversing' valve, the vane 98 is continuously urged toward its lefthand limit position. Accordingly, independently of the position in the cycle of operation to which the shut-off valve |32a is operated the Vane 90 is caused to immediately move to and stop at its lefthand limit.

As further described in connection With Figs. 2 through 9, depending upon the positioning of the recess 2|!) which controls the supply circuit for chamber 38, the parking position may either correspond to or be beyond the normal lefthand limit of travel of the vane 90.

Referring to Figs. 13 and 14, an embodiment of the invention is shown in which the shut-off valve |32 described with reference to Figs. 2 through 9 may also be arranged to selectively change the operating speed of the motor, as well as to control the automatic stopping of the motor at a predetermined limit position. In all respects excepting the feature of modifying the motor operating speed, the construction of the motor on Figs. 13 and 14 may be and preferably is as described with reference to Figs. 2 through 9 and, accordingly, corresponding reference characters are used except as to the distinguishing features.

In Figs. 13 and 14, the shut-cir valve |32b is provided with a land 20| which corresponds to the land |44 on valve |32 (Fig. 4) and which,

upon movement of valve |321) to its extreme righthand position, blocks off the passage 208 Which is associated With the circuit for supplying` uid pressure to the reversing valve chamber |38 (Fig. 5). Valve |3212 is provided with an annular recessed portion 203, which, upon slight movement of valve |32 to the left as viewed in Fig. 14, registers With the passage 208, and serves to permit completion of a fluid pressure supply circuit for the reversing valve chamber |38. Valve |32?) is also provided with a tapered portion 205 Which, in accordance with the position of valve |3219, serves to restrict or enlarge the flow of fluid from the inlet |82 through the main supply passage 207, which leads through the reversing valve to the vane chamber. Valve |3217 is shown in Fig. 14 in its extreme lefthand position, in which the land 20E is out of registry With the valve passage 298 permitting a normal reversing action thereof at the limit of travel as described in connection with Figs. 2 through 9; and in which the tapered portion 205 is so disposed as to permit a maximum flow of fluid through the inlet I 82 around the tapered portion and thence through transverse passage 261 to the `reversing valve and the vane chamber. With this positioning of the parts, accordingly, a maximum operating speed of the motor results. Movement to the right of valve |321) from the position shown in Fig. 14, restricts the 'effective area of the valve passage leading to the passage 207, correspondingly reducing the rate of supply of fluid to the motor vane and effecting a reduction in the speed thereof. Movement of the valve |32b to its extreme righthand position substantially interrupts the flow of iiuid through the main piston passage 201', and also moves the land 20| into blocking relation to the valve passage 298. The remainder of the operating stroke of the motor thus occurs at a relatively slow rate and the motor is brought to rest upon the next arrival thereof at the lefthand liimt position, as described in connection with Figs. 2 through 9.

Figs. 15 to 2l disclose the invention as embodied in a motor of the piston type. In this embodiment, the motor is formed of a main casting member 240, which is bored to provide a piston chamber 244 and a valve chamber 246. A closure plate 242 is secured to member 240 to enclose the otherwise open end of chambers 244 and 246. The chamber 244 slidably receives a piston 248, which may be of conventional construction, and which is rigidly secured to a piston rod 250. The free end of rod 250 extends outwardly of the casting 240 and may be connected to the apparatus to be operated by the motor in any suitable Way. The previously identified co-pending application of the present applicant discloses several preferred embodiments for translating the reciprocating motion of the piston rod 250 into alternate reciprocatory movements of a pair of flexible operating cables, such, for example, as the cables 52 described with reference to the preceding figures.

The chamber 246 houses a piston type valve 252 which functions to reverse the fluid pressure supply and exhaust connections to the portions of chamber 244 on opposite sides of the piston 248, by way of the passages hereinafter described. Valve 252 is provided with portions 254, 256 and 258, which serve to separate and define annular recessed portions 260, 262 and 264.

Recesses 260 and 262 are associated with the reversing connections for the piston chamber 244. The recess 264 is associated with the reversing movements of the valve 252, and forms, with the passage 246, a chamber 265 within Which a fluid pressure may be built up to move valve 252 to the left of the position shown in Fig. 16, against the force of a compression spring 266. Spring 266 is associated with valve 252 in the manner described with reference to the first embodiment.

The admission to and the exhaustion from the just identified chamber 265 of uid pressure is selectively controlled by a valve portion 268, of reduced radius, formed in the piston rod 256, and which cooperates with suitable supply and exhaust passages at the respectively opposite limits of travel of the piston 248, in the manner more particularly described hereinafter.

The various passages formed in the motor casing, which are selectively opened and closed by the valve 252 to control the piston 248, and Which are selectively opened and closed by the piston rod 256 to in turn control the valve 252 may best be described in connection with a description of operation of the motor. As in the previous embodiments, note is here made that only the active passages are given reference characters in the following description. Any passages not given reference characters may be regarded as dead-end passages closed by suitable removable plugs, and which are formed during manufacture as an incident to the formation of the active pas@ sages.

The parts are shown in Fig. 16 with the piston 246 in its lefthand limit position, and with valve 252 in the righthand limit position,` to which position valve 252 is automatically Vmoved upon the arrival of piston 246 to the illustrated limit position. rIhe parts are thus in readiness for the beginning of a rightward movement of piston 246. With the parts in the particular positions shown in Fig. 16, the position of valve 252 is controlled entirely by the compression spring 266, since an exhaust circuit is provided for the valve chamber 266. This exhaust circuit (Figs. 16 and 18) extends from chamber 265 through a passage 2'56, a connecting passage 212, passage 214, around the reduced portion 268 of piston rod 256 which is now in registry with the passage 214, and thence through connecting passages 216 and 218 to the sump. It is noted that passage 216 opens to the exterior face 266 of the motor which face 286 is preferably machined to provide a plane surface along which the motor is secured to a suitable stationary support, which may, in the case of a vehicle Windshield Wiper system, be the block of the vehicle engine. The face 286 is enlarged and openings 262 extend therethrough, to receive mounting studs or the like. The just traced exhaust circuit releases any iiuid previously trapped Within the chamber 265, permitting spring 266 to move valve 252 to the right hand limit position and retain it there until the completion of a iiuid supply circiut for chamber 265, which occurs when the piston 248 reaches its opposite limit of travel as described below.

With the parts in the position shown in Fig. 16 a iluid supply circuit is provided for the chamber space to the left of piston 248 and a fluid exhaust circuit is provided for the chamber space to the right of piston 246. The fluid pressure supply circuit extends (Figs. 26, 19 and 16) from the inlet opening 284, through passage 286, a horizontal `connecting passage 286, transverse passage 266, and into the valve space around the reduced portion 266 of valve 252. From this point, the circuit extends through a transverse passage 292, a longitudinal passage 264, and thence through a short vertical passage 296 into the chamber space on ythe lefthand side of piston 248. The corresponding fluid exhaust circuit extends from the chamber space on the righthand side of piston 248 through connecting passages 298 and 366 into the space around the reduced portion 262 of valve 252, from Which portion the circuit extends to the sump by Way of the exhaust passage 362 which extends through the previously identifled inner Wall 266 of the motor.

As long as the just traced fluid pressure supply and exhaust circuits remain complete accordingly, piston 248 is caused to move to the right as viewed in Fig. 16. The initial rightvvard movement of piston 248 moves the reduced portion 266 f of piston rod 256 out of registry with the previously identied exhaust passage 214, interrupting the exhaust circuit for the valve chamber 265. This action is, however, Without effect since valve 252 is now retained in its righthand position under the inuence of spring 266.

When piston 248 reaches its righthand limit of travel, valve 252 is automatically moved to the lefthand position, which action reverses the connections to the piston chamber 244 and initiates I.

a leftward movement of piston 248. The parts are shown in Fig. 2l with piston 248 in its righthand limit position and with valve 252 in the position to which it is moved upon the arrival of piston 24B at such righthand limit. The uid circuits involved are as follows:

The arrival of piston 246 at its righthand limit of travel brings the reduced portion 266 of piston rod 256 into registry with a vertical passage 364 which connects into the previously identified passage 216. This action completes a fluid pressure supply circuit which extends (Figs. 20 and 16) from the inlet opening 284, around the reduced portion 266 of piston rod 256 and thence through passages 364 and 216 into the previously identified valve chamber 265. Completion of this circuit admits fluid under pressure to the chamber 265, vWhich accordingly builds up a pressure therein and forces valve 252 to the left against the force of the compression spring 266. With valve 252 in the position shown in Fig. 21, a fluid pressure supply circuit is completed for the portion of chamber 244 on the right hand side of piston 246 and an exhaust circuit is provided for the portion of chamber 244 on the lefthand side of piston 248. The fluid pressure supply circuit extends (Figs. 20, 19v and 16) from the inlet opening 284, through passages 286,268 and 296 into the chamber space around the reduced portion 262 of valve 252. From this point the circuit extends through the previously identied passages 298 and 366 into chamber 244. The uid exhaust circuit extends from the portion of chamber 244 on the lefthand side of piston 248 through the previously identified passages 266,294 and 262 into the chamber space around the reduced portion 266 of valve 262. From this point the fluid is discharged by Way of the exhaust passage 366, Which passes through the inner Wall 286 of the motor.

As long as the just traced fluid pressure supply and exhaust circuits remain complete accordingly, piston 248 is caused to move to the left. The initial leftWard movement of piston 246 moves the reduced portion 266 of piston rod 256 out of registry with the valve supply passage 364m terrupting the previously traced huid pressure supply circuit for the valve chamber 265. This action, however, serves merely to trap the previously admitted fluid Within the chamber and has no effectupon the position of valve 262.

When piston 24B reaches the lelthand limit position shown in Fig. 16, the previously traced exhaustl circuit for chamber 265 is again com pleted by the movement of the valve portion 258 of piston rod 253 into registry with the exhaust passage 274. Completion of this exhaust circuit permits valve 252 to be moved to the righthand limit position under the influence of spring 255, :re-completing the initially traced supply and exhaust circuits for chamber 244, and initiating a rightward movement of piston 248. As long, accordingly, as the inlet passage 284 is supplied with iiuid under pressure, the piston 248 continuously reciprocates, valve 252 automatically responding to the arrival thereof at the limit positions. The valve movement at one limit position is effected by the application to the valve of fluid pressure, and the valve movement at the other limit position is effected by spring pressure rendered effective by the exhaustion of the just stated uid pressure.

As in the previously described embodiments, the motor of Figs. 15 through 21 includes special provision to insure proper valve operation under all conditions. It is noted that the portion of the valve chamber 24B between the lefthand end of valve 252 and the end of the chamber is continually connected to the sump by way of a relief passage 358. Passage 338 thus eifectively prevents the building up of a fluid pressure within such valve chamber portion which pressure, unless relieved, might oppose the leftward movement of valve 252. Similarly, a bleeder passage 3 l 0 extends from reduced portion 252 into passage 3H which communicates with chamber 265. As long as valve 252 occupies the position shown in Fig. 16, the valve chamber 255 is thus connected directly to the exhaust port 382 by way of the bleeder passage 3W, thus preventing any premature building up of a pressure within chamber 265 which would otherwise tend to cause a premature operation of the vlave. On the other hand, when valve 252 is in its lefthand limit position as shown in Fig. 21, the valve chamber 255 is connected through the bleeder passage 3H) to the supply passages 292, 288 and 286. Thus, any leakage from the chamber 285, occurring for example around the piston rod 258 by way of passages 2'58, 212 and 274, is compensated for by a continuous supply of iiuid through the bleeder passage 38. This continuous supply effectively prevents a premature loss of pressure in the chamber 235, and accordingly prevents a premature movement of valve 252 to the right under the inuence of the spring 285.

In the foregoing description, the supply passage 284 has been considered as continuously open, resulting in a continuous operation of the motor. In instances where it is desired to arrange the motor so that it may be stopped at any point in its operating cycle, a cut-off valve 3I2 may be interposed in the line 3| 4 leading to the inlet 284. With this arrangement, closure of valve SI2 immediately interrupts the supply of iiuid pressure to the piston 248, bringing it to rest immediately.

Alternatively, if it is desired to cause each stopping operation of the motor to occur at a selected point, as for example, when the motor is used in connection with a vehicle windshield wiper system, the arrangement of Fig. 22 may be used. In Fig. 22, which corresponds generally to Fig. 20, a shut-01T or parking valve 3i3 is interposed between the inlet 2841i and the previously identiied piston rod 25ia. With this arrangement, valve 3| 6, which may correspond in all respects to the shut-off or parking valve l32 described with reference to the first embodiment, selectively completes or interrupts the previously traced uid pressure supply circuit for the valve chamber 265. This action, as described in connection with the first embodiment does not interfere in any way with the completion of the exhaust circuit for chamber 255, so that the normal reversing movement of valve 252 occurs at the lefthand limit of travel of piston 248. The normal reversing movement of valve 252 when piston 248 reaches its righthand limit of travel, however, is prevented since no fluid pressure supply circuit is completed for chamber 265. Valve 252, therefore, remains in the position shown in Fig. 16 and the fluid pressure acts continuously to urge piston 248 to the right. As also described in connection with the first embodiment, the passage 384 which cooperates with i\ the reduced portion 258 on piston rod 258 to complete the just mentioned fluid supply circuit for chamber 265, may be so positioned that it completes this circuit somewhat in advance of the arrival of piston 248 at its mechanical limit of travel. In this instance, when the parking valve 316 is moved to the stopping position, the rightward movement of piston 248 continues to a point beyond the normal limit position, aifording an extra parking movement in the case of a windshield wiper system. In all other respects, the motor indicated in Fig. 22 may be constructed and arranged as described with reference to Figs. l5 through 21.

Referring now to Figs. 23 through 35, the in- I.

vention is shown as embodied in a piston type motor of the single acting type, that is, a motor in which the movement of the piston in one direction is effected by the application thereto of fluid pressure; and the movement of the piston in the other direction is effected by exhausting the ud pressure and applying to the piston the force of a compression spring which may be and preferably is loaded during the power stroke. In this instance, as in the previous instances, the application to and exhaustion from the piston chamber of the fluid pressure is controlled by a reversing valve of the type which is actuated in one direction by fluid pressure and is actuated in the other direction by a return spring. The movements of the reversing valve are selectively controlled in accordance with the position of the piston rod.

The motor designated as a whole as 330 comprises generally a main casting 332 which is formed to provide a piston chamber 334, as well as the hereinafter described valve chambers; and a second casting 335, which is threadably secured to casting 332 and forms a closure for the otherwise open ended piston chamber 332. Member 335 is also formed to provide a spring retaining sleeve 338. The end of sleeve 338 is closed by a cover 340, which is adjustable to elect a corresponding adjustment of the main return spring 342. As most clearly appears in Fig. 26, one end of the return spring 342 bears against the cover 348, and the other end is seated over a boss 344, which is carried by the main motor piston 346.

Piston 345, which is conventionally slidably received within the chamber 334 is rigidly secured to the piston rod 348, which extends longitudinally through the casting 332, and is connected at its outer end to a suitable transmission element represented as a flexible cable or Bowden wire 350. A nipple 352 is threaded into the end of the piston rod passage to close the same, and is provided with a split outer end 354 which acts as a retainer for the sheath 356 provided for cable 350. A tightening nut 358 is threaded over the split portion 354 to restrict the same and bind the sheath 356 in the split portion.

The piston rod 348 is provided with a somewhat elongated Aannular recessed po-rtion 363 which functions as hereinafter described to selectively control the admission to and exhaustion from the valve chamber of fluid pressure, to thereby control the movements of the main reversing valve 362. Piston rod 343 is provided with a second recessed portion' 364 which functions as hereinafter described to exhaust the reversing valve chamber.

The main reversing valve 332 is slidably received in a passage 366 provided therefor in the casting 332, and is movable to the position illusrtrated in Figs. and 29 by the introduction of fluid pressure into the chamber space 338. A compression spring 313, which is received in a recess 312 provided therefor in'valve 362, and one end of which bears directly against the wall 314 of casting 332, continuously urges the valve 362 to the right of the position shown in Figs. 25 and 29. Leftward movement of the valve 352 is limited by the engagement of the lefthand end with the just mentioned wall 314, and rightward movement thereof is limited by the engagement of the righthand end of the valve with a stop313 which is either suitably secured to or formed integrally with a plug 318 which closes the end of the valve housing 363. Reversing valve 362 is provided with an annular recessed portion 383, which as hereinafter described controls the admission to and exhaustion of uid pressure from the main piston chamber 334.

The starting of the motor 330 and the stopping thereof at a selected limit position is controlled by cut-off valve 382, which is slidably received in a passage provided therefor in the casting 332, and is provided with an annular recessed portion 384, which as hereinafter described controls the admission of iiuid pressure to the reversing valve chamber 368. The shank 333 of valve 382 extends outwardly of the casting 332, and is suitably connected to a control cable 333 which may and preferably is of the flexible or Bowden wire type. The sheath 393 for the cable 388 is secured in a split nipple 392, associated with a main nipple 394, in the manner described in connection with the sheath 356 associated 'with the main operating cable 353.

The base of motor 333 is provided with oppositely disposed attaching bosses 393, by which it may be connected to a suitable stationary support which, in the case of windshield wiper systems, is preferably the engine of the vehicle. The base of motor 330, as most clearly appears in Fig. 27, is provided with recessed or undercut portions 439, into which the hereinafter described exhaust passages open, and which recesses may be in communication with a suitable sump. An inlet boss 402 is also formed adjacent the face of the motor, and accommodates the main inlet passage 434, which may be connected in any suitable way to a suitable source of fluid pressure.

The various passages which are formed in the motor to accommodate the circulation of fluid to the piston chamber, and to the valve chamber, may best be described in connection with a description of operation of the motor as a whole. In the following description, only the active fluid passages are given reference characters, those passages not given reference characters being dead end passages, closed by suitable plugs, and which are formed as an incident to the manufacture of the active passages.

As a preliminary to the detailed description of operation, it is noted that the two views of Figs. 36 and 37 clearly show in diagrammatic form the operating and valve passages which are completed at the end of the return and power strokes respectively. The various passages in Figs. 36 and 37 are given the same reference characters as the corresponding passages in the detail figures and the following description may be read either in connection with Figs. 36 and 37, or;

in connection with the figures identified in parenthesis in the description.

rThe parts are shown in Figs. 23 through 35 in positions of readiness for the beginning of a power stroke. That is, the motor piston` 346 is in its righthand limit position, to which it is urged by the main return spring 342, and the reversing valve 332 is shown in its lefthand limit position, to which position it is automatically moved upon the arrival of the piston 346 at the righthand limit of travel. With the parts in these positions, a fluid supply circuit is completed between the previously mentioned inlet 434 and the valve operating chamber 333. This circuit extends (Figs. 25, 27, 28, 29, 31, 33 and 34) from the inlet 434 around the recess of the shutoif valve 302through a vertical passage 413, a longitudinal passage M2, a transverse passage 444 and thence into the space around the recess 339 of the piston rod 348. From this point the circuit extends along the recess 333 and thence through a vertical passage 443 into the chamber 368. This circuit is completed as will be appreciated, when the piston rod recess 339 exposes passage 4i8 which occurs at the end of the return stroke or at the arrival of the piston 346 at the position shown in the drawings. Upon completion of this circuit the thus admitted iiuid builds up a pressure within the valve chamber 368, forcing it to the position shown in thevarious figures, against the force of the compression spring 313 associated therewith.

Movement of the reversing valve 332 to its lefthand limit position as just described completes a iiuid circuit extending from the inlet 404 to the piston chamber 334 at the righthand side of piston 343. This uid circuit extends (Figs. 29 and 31) from the inlet 404 through a transverse passage 423 into the space around the reversing valve recess 333 and thence through a supply passage 422 into the portion of chamber 334 which is on the righthand side of piston 346. In response to completion of this circuit, a fluid pressure is built up in the just mentioned chamber space, which serves to force piston 346 to the left as viewed in the various iigures, against the force of the main return spring 342.

The initial leftward movement of piston 346 moves the piston rod recess 333 out of registry with the vertical passage 443 (Fig. 34), thereby interrupting the previously traced fluid supply circuit for the valve chamber 333, and trapping the fluid within this chamber. Valve 332 accordingly r-emains in its left-hand limit position.

A feature of the present construction is the provision of secondary passages which, during the leftward movement of piston 346, serve to connect valve chamber 363 to the source of supply in order to replace any of the iiuid which may have leaked therefrom, and overcome any otherwise possible tendency for valve 362 to move to the right prior to the end of the power stroke. One of these secondary fluid supply circuits extends (Figs. 25, 27, 28, 29, 31 and 32) from the inlet 464, through the cut-o valve recess 384, vertical passage 4M, longitudinal passage M2, and transverse passage 426 into the piston rod recess 366, which is now in registry with passage 424. From this point the circuit extends through transverse passage 426, longitudinal passage 428, and vertical passage 436 into the valve chamber 368. It is noted with reference particularly to Fig. 33, that the vertical passage 436 is closed as long as reversing valve 362 occupies its right hand position, but is exposed by the previously described movement thereof of the valve to the lefthand limit position. During completion of the just traced circuit accordingly, valve chamber 368 is connected to the source of supply and any leakage lfrom the valve chamber 368 is replaced.

The second of the just mentioned secondary circuits extends (Figs. 25, 2'?, 28, 29, 31, 32 and 33) from the inlet 464 through the cut-off valve recess 384, vertical passage 4M), and transverse passage 432 to the recess 366 of the piston rod 348, which latter element is now in registry with passage 432. From this point the secondary circuit extends through transverse passage 434 into the previously mentioned longitudinal passage 428 and thence through vertical passage 436 into the valve chamber 368. During completion of this circuit accordingly, any leakage is again replaced. Recess S66 is so proportioned as to overlap passages 424- and 432, so that 432 will be uncovered before passage 424 is covered, thus ensuring that fluid will be delivered to passages 428 and 436 at all times except when recess 366 occupies a position to the left of passage 432 or to the right of passage 424. Recess 366 registers with passage 424 very shortly after the beginning of a power stroke and does not move out of registry with passage 432 until just prior to the completion of the power stroke.

As the piston 346 approaches its extreme lefthand position, the reduced portion 364 of piston rod 348 (Fig. 26) passes beyond and exposes the valve chamber exhaust passage 436 (Fig. 35), completing an exhaust circuit for the valve chamber 368. This circuit extends (Figs. 25, 29, and 35) from the valve chamber 368 through the previously mentioned vertical passage 446 into the space around the reduced portion 364 of piston rod 368 which is now in registry with this passage. From this point the circuit extends directly through the exhaust passage 436 to the sump or other collecting point. Upon completion of the just traced exhaust circuit, the compression spring 3l() (Fig. 25) is rendered effective to force the reversing valve 362 to the right, to its righthand limit position in engagement with the stop 36.

The just mentioned movement of the reversing valve 362 to its righthand limit position interrupts the previously traced supply circuit for the piston chamber 334, and completes an exhaust circuit therefor', which circuit extends (Figs. 25 and 32) from the chamber 334 through the passage 422 and into the reversing valve recess 380. From this point the circuit extends directly through the exhaust passage 438 into the sump. It will be appreciated that with valve 362 in the righthand limit position, the previously mentioned supply passage 420 (Fig. 3l) is closed off by the valve.

Completion of the just traced exhaust circuit for the chamber 334 renders the main return spring 342 effective to force piston 346 to the right through the return stroke thereof, which return stroke is interrupted by the engagement of the piston 346 with the mechanical stop 440 provided therefor in the piston chamber 334; or alternatively, it may be interrupted slightly prior to this engagement by the automatic movement of the reversing valve 362 to its lefthand position as described below. The initial rightward movement of piston 346 moves the reduced portion 364 of piston rod 348 (Fig. 26) out of registry with the exhaust passage 436, interrupting the previously traced exhaust circuit for the reversing valve 362. Valve 362 is, however, now in its righthand limit position so that the interruption of this circuit is without effect. As the rightward movement of piston 346 progresses, the reduced portion 366 of piston rod 348 is successively brought into and out of registry with the previously mentioned secondary passages 432 and 424, tending to cause completion of the previously traced secondary fluid supply circuits for the valve chamber 368. Completion of these circuits is, however, prevented since the vertical passage 438 (Fig. 33) associated with the secondary circuits is now closed off by the enlarged portion 442 of the reversing valve 362. The secondary circuits are, therefore, effective only during a power stroke of the motor, or during a stroke in which the valve 362 is in its lefthand limit position.

As piston 346 approaches the righthand limit of its stroke, the recess 366 of piston rod 348 is again brought into registry with and opens the valve supply passage 4l6 (Fig. 34), thereby recompleting the initially traced fluid pressure supply circuit for the valve chamber 368. For convenience, this supply circuit is repeated as follows: Figs. 27, 28, 31, 33 and 34 from the inlet 484 around the shut-off valve recess 384, passages 450, 442, 4|4 into the piston rod recess 360, and thence through the vertical passage 4|6 into the valve chamber 368. Upon completion of this circuit, a fluid pressure is built up within the chamber 368, which forces valve 362 to the left against the force of the compression spring 310. This movement of reversing valve 362 closes off the previously mentioned piston chamber exhaust port 438 (Fig. 32) and re-opens the piston chamber supply port 420 (Fig. 31). This latter action re-ccmpletes the above traced fluid pressure supply circuit for the piston chamber 334', initiating a leftward movement of the piston 346 in the previously described manner.

As long, accordingly, as the shut-off valve 382 remains in the running position shown in Fig. 27, the piston 346 continuously reciprocates, the leftward movement thereof, or the power stroke thereof, being effected by the application of fluid pressure to piston 346, and the return stroke thereof being effected by the force applied thereto by the main return spring 342. During this operation of the piston also, reversing valve 362 occupies its lefthand limit position during each power stroke and is returned to its righthand position by the return spring 316 at the conclusion of each power stroke. The conclusion of each power stroke also completes an exhaust circuit for the valve chamber 368 and the conclusion of each return stroke completes a supply circuit for the valve chamber 368.

Considering now the stopping action of the motorof Figs. 23 through 35, itis believed to be evident from Fig. 27 and Fig. 3l that the shutoff valve 332 functions only to directly control the fluid pressure supply circuit for the valve chamber N8, and is not directly associated with the supply or exhaust circuits for the main piston chamber 331i. It is believed to be evident also that a movement of the shut-olf valve 332 to left as viewed in Fig. 27, brings the enlarged portion Edil thereof into registry with and closes off the passage lili) (Fig. 3l) leading to the valve chamber Stil. The shut-off valve "332 may, therefore, be operated at any point in the power or return stroke of motor 33d without other immediate effect than to prevent completion, at the conclusion of the next return stroke, of a fluid pressure supply circuit for the valve charnber 358. This uid pressure supply circuit being interrupted, the reversing valve Sdi remains in its righthand position after the arrivalof piston 346 at its normal lefthand limit and a reversal of the motor, therefore, does not result. In the stopped position, also, the piston till@ is continuously acted upon by the return spring ist and is thus resiliently retained thereby in its stopped position.

As will be appreciated, if ythe normal completion of a fluid pressure supply circuit for the `valve chamber 36S occurs simultaneously with the arrival of the piston 3% at mechanical sto-p 440 provided therefor (Fig. 26), such stop Mit will serve to bring the piston Edf to rest at the same point at which its reversal normally ocvcurs during continuous operation of the motor.

In certain instances, as described in connection K with the earlier embodiments, particularly 'where the approved' moto-r is used to drive a.

windshieldwiper mechanism, it is desirable to bring the motor to rest with the piston thereof at. a positionA beyond the normal limit of its movements. with the present construction it is only necessary to so proportion the parts that the fluid pressure supply circuit for the valve chamber Edil is completed at a time when the piston tilt is still in predetermined spaced relation 'to the mechanical stop Mil; that is, to so proportion the parts that the piston rod recess Stil exposes the valve chamber supply passage :it (Fig' 34) a predetermined time before piston dit reaches the mechanical stop du With this proportioning, the normal reversal of movement of piston 3ds will occur at a point spaced from the stop drill. If the shut-offv valve 332, however, is moved to the stopping position, preventing completion of the iluid pressure supply circuit for the valve chamber 368, no interruption in the movement of the piston. 3dS will occur upon the exposure of the supply passage M6. On the contrary, the piston movement will continue beyond its normal linut and will be stopped when piston engages the mechanical stop fi/lt.

In addition to the previously mentioned secondary passages 424 and Q32, etc. (Fig. 23) which serve to prevent a premature movement to the right of reversing valve 362 as a consequence of any leakage which may occur in the piston, the present invention also provides additional secondary fluid exhaust circuits to prevent faulty operation of piston 366, as well as to prevent faulty operation of the reversing valve 362. Referring, particularly to Fig. 28, an exhaust opening (itil is provided in the chamber 33d adjacent the left hand end thereof, which leads directly into the let To accomplish ,this in accordance sump or other collecting vessel, and prevents the building up of a pressure within chamber 3,34 to `the left of piston 34E as a consequence of any leakage which may occur around the piston 31%. Similarly, as clearly appears in Fig. 25, anexhaust passage 0352 leads from the chamber space at the lefthand end of reversing valve 362, through which any fluid which may leak around the enlarged portion 451i thereof may escape, thus avoiding any possibility of building up of pressure upon such lefthand end of the valve which would interfere with proper operation thereof.

A bleeder hole ll, of relatively small area, is formed in the head of valve 362 to provide a con tinuously open passage from chamber 3b@ to the sump, by way of the spring recess 312 and out- The purpose of this bleeder passage is to prevent the building up of pressure in chamber 'ii during the return or rightwardstroke of piston 346, by leakage from any of thehigh pressure fluid passages. The bleeder hole being of smaller area than passage dit, pressure is maintained in chamber 368 when the latter'passage is open in spite of the continuous leakage through (itil. Asvpreviously stated, the initial power movement of piston 3443 closes olf the supply passage l l 6. Shortly thereafter, however, the previously traced auxiliary fluid passages ili and A132 become effective to supply fluid to chamber 368 through passage @353. The proportioning of the parts is such that only a negligible leakage from chamber 36s through bleeder passage occurs between the closure of passage (lit and the opening of passage @39.

In order to prevent faulty operation of the shut-off valve 382, the chamber space at the left-hand end thereof (Fig. 27) is continuously connected to exhaust through a secondary passage lli, and the chamber space at the rightn hand side thereof is 'continuously connected to exhaust through a secondary passage #158. It is seen, therefore, that any internal oil leakages which may occur around the moving Parts of the motor, are'fully compensated for and rendered of no effect. As to external oil leakages, it will be appreciated that an oil-tight connection may be made between the base of the motor and the supporting structure, thus effectively overcoming any leakage at this point.

Although only a few illustrative embodiments of the invention have been described, it will be appreciated that the invention may be embodied in many further and widely different forms. The described embodiments, accordingly, are to be rewarded in an illustrative and not in a limiting sense. v

What is claimed is: f

l. Fluid pressure operated motor mechanism comprising, in combination, a member disposed to be moved between rst and second limit posi tions under the influence of a fluid pressure differential; a reversing valve movable between nrst and second positions to control the direction of movement of said member; continuously acting means for urging said valve to one of said positions; rneans including a passage opened and closed by movement of said member for applying fluid pressure to said valve to cause it to move to said other position and for relieving said fluid pressure; and means including a secondary passage rendered eifective when said valve is in said other position for applying fluid pressure thereto.

2. Fluid pressure operated motor mechanism comprising, in combination, a member disposed to be moved between rst and second limit positions under the influence of a fluid pressure differential; a reversing valve movable between first and second positions to control the direction of movement of said member; continuously acting means for urging said valve to one of said positions; means including a passage opened and closed by movement of said member for applying fluid pressure to said valve to cause it to move to said other position and for relieving said iiuid pressure; and means dening a secondary passage for exhausting uid from said valve to thereby prevent the building up of a pressure in opposition to said first mentioned pressure.

3. Fluid pressure operated motor mechanism comprising, in combination, a housing formed to dene a vane chamber and a valve chamber; a Vane operatively mounted in said vane chamber and disposed to be moved therein in respectively opposite directions under the inuence of uid pressure; a shaft for said vane; a piston type reversing valve movably mounted in said valve chamber and disposed to control the direction of operation of said vane; continuously acting means for urging said valve to one limit position thereof; means for admitting iiuid pressure to said valve chamber to move said valve to an opposite limit position and for exhausting said uid pressure including means defining a fluid circuit leading to said valve chamber; said shaft having port means alternately registerable with said passage to cause said valve chamber to be supplied With fluid pressure when said vane reaches one limit position and to cause said valve chamber to be exhausted when said vane reaches the other` limit position.

4. Fluid pressure operated motor mechanism comprising, in combination, a member disposed to be moved under the influence of a uid pressure differential; a reversing valve movable between rst and second positions to control the direction of movement of said member; continuously acting means for urging said valve to one of said positions; means for subjecting said valve to fluid pressure to cause it to move to the other of said positions and for exhausting said fluid pressure; and means for stopping said motor comprising means for completing an auxiliary exhaust circuit for said valve.

5. Fluid pressure operated motor mechanism comprising, in combination, a member disposed to be moved under the influence of a iiuid pressure differential; a reversing valve for controlling the direction of movement of said member; a housing formed to dene chambers for said member and said valve; inlet and exhaust means associated With said member and said valve; and a single stop control device selectively movable to control said inlet means to vary the speed of movement of said member and to control said valve to cause said motor to stop in a selected position.

6. Fluid pressure operated motor mechanism comprising, in combination, a housing formed to define a vane chamber and a valve chamber; a vane operatively mounted in said vane chamber and disposed to be moved therein in respectively opposite directions under the infiuence of fluid pressure; a shaft for said vane; a piston type reversing valve movably mounted in said valve chamber and disposed to control the direction of operation of said vane; continuously acting means for urging said valve to one limit position thereof; means for admitting fluid pressure to said valve chamber to move said valve to an opposite limit position and for exhausting said fluid pressure including means dening a fluid circuit leading to said valve chamber; said shaft naving port means alternately registerable with said circuit to cause said valve chamber to be supplied with uid pressure When said vane reaches one limit position and to cause said valve chamber to be exhausted when said vane reaches the other limit position; and stop control means including means associated with said valve chamber for preventing the building up of a pressure in said valve chamber.

7. Fluid pressure operated motor mechanism comprising, in combination, a housing formed to define a vane chamber and a valve chamber; a vane operatively mounted in said vane chamber and disposed to be moved therein in respectively opposite directions under the influence of fluid pressure; a shaft for said vane; a piston type reversing valve movably mounted in said valve chamber and disposed to control the direction of operation of said vane; continuously acting means for urging said valve to one limit position thereof; means for admitting fluid pressure to said valve chamber to move said valve to an opposite limit position and for exhausting said Huid pressure including means defining a fluid circuit leading to said valve chamber; said shaft having port means alternately registerable with said circuit to cause said valve chamber to be supplied with iiuid pressure when said vane reaches one limit position and to cause said valve chamber to be exhausted when said vane reaches the other limit position and stop control means including a valve associated with said fluid circuit and operable to prevent a building up of pressure through said fluid circuit in said valve chamber.

8. Fluid pressure operated motor mechanism comprising, in combination, a housing formed to denne a vane chamber and a valve chamber; a vane operatively mounted in said vane chamber and disposed to be moved therein in respectively opposite directions under the influence of iluid pressure; a shaft for said vane; a piston type reversing valve movably mounted in said valve chamber and disposed to control the direction of operation of said vane; continuously acting means for urging said valve to one limit position thereof; means for admitting fluid pressure to said valve chamber to move said valve to an opposite limit position and for exhausting said fluid pressure including means defining a pair of branch fluid circuits each adapted to be placed in communication with said valve chamber; said shaft having a first port associated with one of said branch circuits and arranged to place the associated branch circuit in communication with said valve chamber when said vane approaches one limit of its travel and having a second port associated with the other of said branch circuits and arranged to place said other branch circuit in communication with said valve chamber as said vane approaches the other limit of its travel.

HUMPHREY F. PARKER. 

